1. MICROSCOPES

2. The microscope is an instrument that allows us to see objects that are normally too small for the eye to see It was invented by Anton VanLeewenhoek in the 1600’s Robert Hooke was the 1 st to see cells

3. Types of Microscopes 1.Simple Microscope – a single lens (eg. magnifying glass)

4. 2. Compound Light Microscope – light is projected through 2 lenses to view an “image” of an object. The image is somewhat blurry. BEST FOR VIEWING LIVE SPECIMENS pg. 16 – Human Cheek Cells - cell organelles stained green and nuclei yellow pg. 29 – Egg Cell – surrounded by smaller cells that support and nourish egg

5. 3. Electron Microscope – uses a beam of electrons to take a magnified ‘picture’ of an object. eg. T.E.M. – Transmission Electron Microscope designed by James Hillier to view specimen, it is encased in plastic and shaved into very thin layers, allowing electrons to pass through it, therefore can only be used to view dead cells pg. 19 – goblet cell pg. 37 - lysosome

6. eg. S.E.M. – Scanning Electron Microscope reflects electrons from the surface of the specimen, allowing thicker specimens to be used The electron microscope can magnify objects to a very large size. The picture of the object is very clear. pg. 21 – RBC pg. 27 – Sperm Cells pg. 148 -RBC & capillary

7. Important Vocabulary Magnification – apparent enlargement of an object - a magnification of 100X means that the object is 100 times bigger than the actual object Resolution – clarity, sharpness - the ability of a microscope to show two very close points

8. Electron MicroscopeCompound Microscope Approximate SizeSeveral m 3 Compact Cost$ 10 6 Max. $3000 Magnification ‘enlargement of an object’ > 10 6 400 – 1000 max. Resolution ‘clarity, sharpness’ Very highLimited by wavelength of light Training2 years (tech)1 class IlluminationElectron beamLight

10. Characteristics of a Compound Light Microscope 1.When you go from low to medium to high power the: light gets dimmer field of view gets smaller image gets bigger 2. The ‘image’ of an object under the microscope appears “backwards” For our school microscopes to calculate total magnification: Total Mag : objective power x ocular lens (10X) Low Mag : 4X10= 40X Med Mag:10X10= 100X High Mag:40X10= 400X

11. The Diameter of the Field of View Magnification Ocular Objective Specimen Magnification Field of View Diameter (mm) (um) diagram 10X4X(low) 10X(med) 10X(high) Converting mm --- µmSample Calculation: 4 mm = 1 mm = µm

12. Activity 1.Estimation of Specimen Size – handout 2.Using prepared slides, Letter e, HYDRA and Volvox, sketch and estimate actual size Diagram - diagram is done in pencil - sketch (stipple) diagram on left side of blank paper & labels on right - diagram needs a title - include total magnification